Bluetooth: Audio: Add support for encrypted broadcast

Add support for adding a broadcast code to the broadcast
source.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>

include/zephyr/bluetooth/audio/audio.h

@@ -17,6 +17,7 @@
 #include <zephyr/bluetooth/hci.h>
 #include <zephyr/bluetooth/iso.h>
 #include <zephyr/bluetooth/gatt.h>
+#include <zephyr/bluetooth/audio/bap.h>
 #include <zephyr/bluetooth/audio/lc3.h>
 
 /**
@@ -2085,6 +2086,12 @@ struct bt_audio_broadcast_source_create_param {
 	 *  controller may ignore.
 	 */
 	uint8_t packing;
+
+	/** Whether or not to encrypt the streams. */
+	bool encryption;
+
+	/** @brief Broadcast code */
+	uint8_t broadcast_code[BT_BAP_BROADCAST_CODE_SIZE];
 };
 
 /** @brief Create audio broadcast source.

samples/bluetooth/broadcast_audio_source/src/main.c

@@ -113,6 +113,7 @@ static int setup_broadcast_source(struct bt_audio_broadcast_source **source)
 	create_param.params_count = ARRAY_SIZE(subgroup_param);
 	create_param.params = subgroup_param;
 	create_param.qos = &preset_16_2_1.qos;
+	create_param.encryption = false;
 
 	printk("Creating broadcast source with %zu subgroups with %zu streams\n",
 	       ARRAY_SIZE(subgroup_param),

subsys/bluetooth/audio/broadcast_source.c

@@ -735,6 +735,12 @@ int bt_audio_broadcast_source_create(struct bt_audio_broadcast_source_create_par
 	source->qos = qos;
 	source->packing = param->packing;
 
+	source->encryption = param->encryption;
+	if (source->encryption) {
+		(void)memcpy(source->broadcast_code, param->broadcast_code,
+			     sizeof(source->broadcast_code));
+	}
+
 	LOG_DBG("Broadcasting with ID 0x%6X", source->broadcast_id);
 
 	*out_source = source;
@@ -883,6 +889,11 @@ int bt_audio_broadcast_source_start(struct bt_audio_broadcast_source *source,
 	param.packing = source->packing;
 	param.interval = source->qos->interval;
 	param.latency = source->qos->latency;
+	param.encryption = source->encryption;
+	if (param.encryption) {
+		(void)memcpy(param.bcode, source->broadcast_code,
+			     sizeof(param.bcode));
+	}
 
 	err = bt_iso_big_create(adv, &param, &source->big);
 	if (err != 0) {

subsys/bluetooth/audio/endpoint.h

@@ -7,6 +7,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/bluetooth/audio/bap.h>
 #include <zephyr/kernel.h>
 #include <zephyr/types.h>
 
@@ -75,6 +76,7 @@ struct bt_audio_broadcast_stream_data {
 struct bt_audio_broadcast_source {
 	uint8_t stream_count;
 	uint8_t packing;
+	bool encryption;
 	uint32_t broadcast_id; /* 24 bit */
 
 	struct bt_iso_big *big;
@@ -83,6 +85,8 @@ struct bt_audio_broadcast_source {
 	/* The codec specific configured data for each stream in the subgroup */
 	struct bt_audio_broadcast_stream_data stream_data[BROADCAST_STREAM_CNT];
 
+	uint8_t broadcast_code[BT_BAP_BROADCAST_CODE_SIZE];
+
 	/* The subgroups containing the streams used to create the broadcast source */
 	sys_slist_t subgroups;
 };

subsys/bluetooth/shell/audio.c

@@ -1534,7 +1534,7 @@ static int cmd_create_broadcast(const struct shell *sh, size_t argc,
 	struct bt_audio_broadcast_source_stream_param
 		stream_params[ARRAY_SIZE(broadcast_source_streams)];
 	struct bt_audio_broadcast_source_subgroup_param subgroup_param;
-	struct bt_audio_broadcast_source_create_param create_param;
+	struct bt_audio_broadcast_source_create_param create_param = { 0 };
 	struct named_lc3_preset *named_preset;
 	int err;
 
@@ -1545,12 +1545,51 @@ static int cmd_create_broadcast(const struct shell *sh, size_t argc,
 
 	named_preset = default_preset;
 
-	if (argc > 1) {
+	for (size_t i = 1U; i < argc; i++) {
-		named_preset = set_preset(false, 1, &argv[1]);
+		char *arg = argv[i];
-		if (named_preset == NULL) {
+
-			shell_error(sh, "Unable to parse named_preset %s",
+		if (strcmp(arg, "enc") == 0) {
-				    argv[1]);
+			if (argc > i) {
-			return -ENOEXEC;
+				size_t bcode_len;
+
+				i++;
+				arg = argv[i];
+
+				bcode_len = hex2bin(arg, strlen(arg),
+						    create_param.broadcast_code,
+						    sizeof(create_param.broadcast_code));
+
+				if (bcode_len != sizeof(create_param.broadcast_code)) {
+					shell_error(sh, "Invalid Broadcast Code Length: %zu",
+						    bcode_len);
+
+					return -ENOEXEC;
+				}
+
+				create_param.encryption = true;
+			} else {
+				shell_help(sh);
+
+				return SHELL_CMD_HELP_PRINTED;
+			}
+		} else if (strcmp(arg, "preset") == 0) {
+			if (argc > i) {
+
+				i++;
+				arg = argv[i];
+
+				named_preset = set_preset(false, 1, &arg);
+				if (named_preset == NULL) {
+					shell_error(sh, "Unable to parse named_preset %s",
+						    arg);
+
+					return -ENOEXEC;
+				}
+			} else {
+				shell_help(sh);
+
+				return SHELL_CMD_HELP_PRINTED;
+			}
 		}
 	}
 
@@ -1955,7 +1994,8 @@ SHELL_STATIC_SUBCMD_SET_CREATE(audio_cmds,
 #if defined(CONFIG_BT_AUDIO_BROADCAST_SOURCE)
 	SHELL_CMD_ARG(select_broadcast, NULL, "<stream>",
 		      cmd_select_broadcast_source, 2, 0),
-	SHELL_CMD_ARG(create_broadcast, NULL, "[codec] [preset]",
+	SHELL_CMD_ARG(create_broadcast, NULL,
+		      "[preset <preset_name>] [enc <broadcast_code>]",
 		      cmd_create_broadcast, 1, 2),
 	SHELL_CMD_ARG(start_broadcast, NULL, "", cmd_start_broadcast, 1, 0),
 	SHELL_CMD_ARG(stop_broadcast, NULL, "", cmd_stop_broadcast, 1, 0),

tests/bluetooth/bsim_bt/bsim_test_audio/src/broadcast_source_test.c

@@ -128,6 +128,7 @@ static int setup_broadcast_source(struct bt_audio_broadcast_source **source)
 	create_param.params = subgroup_params;
 	create_param.qos = &preset_16_2_2.qos;
 	create_param.packing = BT_ISO_PACKING_SEQUENTIAL;
+	create_param.encryption = false;
 
 	printk("Creating broadcast source with %zu subgroups and %zu streams\n",
 	       ARRAY_SIZE(subgroup_params), ARRAY_SIZE(stream_params));